The number of children diagnosed with autism in America has risen alarmingly over the past fifteen years, in exact step with the rise in the use of glyphosate (Roundup) on corn and soy crops. Coincidence? I think not. In parallel, children in the United States have been burdened with an increased aluminum load from the world's most comprehensive vaccination schedule. Glyphosate has a number of known biological effects that align with the known pathologies associated with autism. Glyphosate also likely promotes aluminum uptake into the tissues. Aluminum, a well-documented neurotoxin, is the established cause of dialysis dementia. I propose that aluminum accumulation in the brain, synergistically promoted by glyphosate, is the principal cause of autism in the US.